Re: [PATCH] x86, tsc: downgrade message for fast calibration failure

From: Joe Perches
Date: Wed Sep 26 2012 - 07:20:09 EST


On Wed, 2012-09-26 at 12:09 +0200, Paul Bolle wrote:
> When fast calibration of the TSC fails an error is printed:
> tsc: Fast TSC calibration failed
[]
> 1) By the way, it's debatable whether this message should be printed at
> informational or at notice level. But the difference between KERN_NOTICE
> and KERN_INFO is too subtle for me. I even find the difference between
> KERN_ALERT and KERN_CRIT, and between KERN_ERR and KERN_WARNING a bit
> subtle. Are there guidelines for choosing between those levels?

The only guidelines I know are the comments in kern_levels.h
and Documentation/kernel-parameters.txt

#define KERN_EMERG KERN_SOH "0" /* system is unusable */
#define KERN_ALERT KERN_SOH "1" /* action must be taken immediately */
#define KERN_CRIT KERN_SOH "2" /* critical conditions */
#define KERN_ERR KERN_SOH "3" /* error conditions */
#define KERN_WARNING KERN_SOH "4" /* warning conditions */
#define KERN_NOTICE KERN_SOH "5" /* normal but significant condition */
#define KERN_INFO KERN_SOH "6" /* informational */
#define KERN_DEBUG KERN_SOH "7" /* debug-level messages */

> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
[]
> @@ -374,7 +374,7 @@ static unsigned long quick_pit_calibrate(void)
> goto success;
> }
> }
> - pr_err("Fast TSC calibration failed\n");
> + pr_info("Fast TSC calibration failed\n");
> return 0;

Perhaps wordsmithing failed to unsuccessful might make
the message seem less like an error and more like an
ordinary occurrence.

Perhaps:

arch/x86/kernel/tsc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index cfa5d4f..4e22540 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -374,7 +374,7 @@ static unsigned long quick_pit_calibrate(void)
goto success;
}
}
- pr_err("Fast TSC calibration failed\n");
+ pr_info("Fast TSC calibration unsuccessful\n");
return 0;

success:
@@ -521,7 +521,7 @@ unsigned long native_calibrate_tsc(void)

/* The alternative source failed as well, disable TSC */
if (tsc_ref_min == ULONG_MAX) {
- pr_warn("HPET/PMTIMER calibration failed\n");
+ pr_warn("HPET/PMTIMER calibration unsuccessful\n");
return 0;
}

@@ -540,7 +540,7 @@ unsigned long native_calibrate_tsc(void)

/* The alternative source failed, use the PIT calibration value */
if (tsc_ref_min == ULONG_MAX) {
- pr_warn("HPET/PMTIMER calibration failed. Using PIT calibration.\n");
+ pr_warn("HPET/PMTIMER calibration unsuccessful. Using PIT calibration.\n");
return tsc_pit_min;
}



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